The OEIS is supported by the many generous donors to the OEIS Foundation.

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A215467 Length of longest palindromic prefix of (n base 2). 5
 1, 1, 1, 2, 1, 3, 2, 3, 1, 4, 3, 3, 2, 2, 3, 4, 1, 5, 4, 4, 3, 5, 3, 3, 2, 2, 2, 5, 3, 3, 4, 5, 1, 6, 5, 5, 4, 4, 4, 4, 3, 3, 5, 5, 3, 6, 3, 3, 2, 2, 2, 6, 2, 2, 5, 5, 3, 3, 3, 3, 4, 4, 5, 6, 1, 7, 6, 6, 5, 5, 5, 5, 4, 7, 4, 4, 4, 4, 4, 4, 3, 3, 3, 3, 5, 7, 5, 5, 3, 3, 6 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,4 COMMENTS Since the binary expansion of n always begins with a 1, a final 0 can't affect the result, so a(2n) = a(n). LINKS N. J. A. Sloane, Table of n, a(n) for n = 0..10000 EXAMPLE ... 4 = 100 -> 1 5 = 101 -> 3 6 = 110 -> 2 7 = 111 -> 3 8 = 1000 -> 1 9 = 1001 -> 4 ... MAPLE rev := proc(lis)     local t1, n, i;     t1:=[]; n:=nops(lis);     for i from 1 to n do t1:=[op(t1), lis[n+1-i]]; end do;     return t1; end proc; isPal := proc(L)     local d ;     for d from 1 to nops(L)/2 do         if op(d, L) <> op(-d, L) then             return false;         end if;     end do:     return true; end proc: A215467L := proc(L)     local a, c;     a := 1 ;     for c from 2 to nops(L) do         if isPal( [op(1..c, L)] ) then             a := c ;         end if;     end do:     return a; end proc: A215467 := proc(n)     if n <= 1 then 1;     else rev(convert(n, base, 2)) ;         A215467L(%) ;     end if; end proc: CROSSREFS Cf. A050430, A215469. Sequence in context: A097285 A057432 A302295 * A284266 A317988 A038568 Adjacent sequences:  A215464 A215465 A215466 * A215468 A215469 A215470 KEYWORD nonn,base AUTHOR N. J. A. Sloane, Aug 11 2012 STATUS approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recents
The OEIS Community | Maintained by The OEIS Foundation Inc.

Last modified August 14 17:07 EDT 2022. Contains 356122 sequences. (Running on oeis4.)